Engine change problem. Water pump impeller chewed up....Where's the pieces?
 

Hello all...I am in the process of installing my new/used engine after throwing the rod in August. I was thinking that I would reuse the water pump from my blown engine as it only had a couple of thousand miles on it. When I removed it, the impeller was chewed completely up. It seems that when the engine blew, metal pieces from the engine case, rods or pistons entered the water channels and destroyed the pump. Any suggestions on how to clean out the cooling system short of removing everything?

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Actually, I'd go the other way around; your water pump may have came apart (on the track, if memory serves), and the bits blocked some of the water passages to your head and more importantly, the oil cooler area, and that is probably what started the fatal chain of events leading to your rod failure. Not that uncommon, this is why Jake is suggesting changing out the water pump every three years, even if it is working fine...........

Getting all the bits out is a major pain, probably will require total disassembly unless you are very lucky.

If one of those pieces, as small as a pencil eraser gets in the right cylinder head capillary, you'll have a cracked head.

You must disassemble the entire cooling system and clean every part.. A flush won't cut it.

If it were mine I'd change the radiators and throw the old ones away.. Gotta take this seriously, if not you'll pay the price the hard way..

Yikes! Agreed that your woes are not over. Impeller grenade fragments have lodged themselves in every nook and cranny of your cooling system. Hard to say at this point whether it was chicken or egg (failed rod or failed impeller) that went first. Was your replacement water pump a factory Porsche part or aftermarket?

I may be missing something but I think he did change out his water pump, because he stated that it only has a few thousand miles on it.

Yes yes, understood.

Inquiring minds want to know if when the WP was changed, it was replaced with a Porsche factory part or an aftermarket supplier (i.e. less expensive/less reliable) part. My car is at 92k and I will be replacing my wp soon as a preventative measure. Knowing the source of potentially unreliable replacement water pumps is of keen interest to me, and probably other Boxster owners as well.

They all fail.. No matter if its OE or not.. No brand is better or worse than another in my experience.

This is why it should be changed on a regular basis.

Definitely going to clean the cooling system....
 

and have the radiators vatted. I will have to further evaluate replacing the radiators as I am out of MONEY! The water pump was 8 months old at the time of the explosion, and was an after market unit from NAPA. The car was not running hot prior to blowing up so I am pretty certain that it was engine parts that destroyed the impeller and not vice versa. Thanks all for the input.

I thought Jake knew of a specific
 

OEM water pump supplier to Porsche that was much better than the others. One he sold. I thought he said that on a forum a while back. Recent experience now says that isn't right? Or is all he is now saying that they all eventually fail?

Same recollection here. When I change mine out, I want the most robust replacement.

Afraid I cannot agree………..
 

If your engine had already “detonated”, and was in the process of stopping when shrapnel got to the pump vanes, you wouldn’t be searching for the vanes, they would still be near the pump, along with the chunk(s) of metal shrapnel that tore them loose (which also would not have have had time to been reduced to small bits and dispersed). If the vane debris totally disintegrated and made it all the way to the radiators, they had to have time to do so; the pump failed first.

quoting Mike "I thought Jake knew of a specific OEM water pump supplier to Porsche that was much better than the others. One he sold. I thought he said that on a forum a while back."

That's what I recall also. For some reason, the peeps at FSI becaome very evasive when asked which brand of pump that is, exactly. Seems to be some kind of a secret.

My car still has the original water pump - 12 years and 116K kilometres later. Because of all the dire warnings, I'm going to change it before I drive the car again in the spring. The fact remains, however, that it has been in there three times longer than recommended and has not detonated.

Hard to know what to think sometimes. :confused:

Not evasive at all.. Because we never know what pump we will be getting from Porsche, which is where we source them from.

No pump has proven to be better than any others at this point, just know that they ALL need to be changed every 3 years, no matter the mileage if you intend to prevent failures from occurring.

But you don't know that.. The pumps do not have to catastrophically fail, make noise of seize to cause engine failures.. One chip from an impeller blade is all it takes to wipe out an engine.

There is nothing dumb about preventive maintenance, if yours hasn't failed it needs to be changed so it doesn't fail. I come from an Aviation background, I take preventive procedures seriously and thats why those who have us service their vehicles never have engine failures.

Like playing Russian Roulette? Some must because they do it everyday even though they know what the repercussions could be.

Now I don't know what to do. I too was thinking of replacing my water pump in the spring, and using the Flat6 pump because, like Mark T and Mike Focke, had seen that it was a better pump.

Flat6 $314, Suncoast $234, both with gasket

At some points we have thought that one pump was better than another, but the fact is that it hasn't been..

Until we step up and have something made from billet it probably won't be.. The problem with that is that not enough people will buy it, based on the price point.. Everyone is concerned with price on the water pump, so just changing the pump every 3 years is the way more people will go..

Maybe at some point enough people will be willing to spend more money for something thats bulletproof, but it seems those people end up buying our complete engine anyway, sometimes when they haven't even had a failure~

Can just the impeller be replaced on a stock water pump? Maybe make a special FSI or LNE impeller can be produced and retrofitted onto a Porsche pump? Would be a cheaper route IF that's possible.

Quote:

Originally Posted by JFP in PA If your engine had already “detonated”, and was in the process of stopping when shrapnel got to the pump vanes, you wouldn’t be searching for the vanes, they would still be near the pump, along with the chunk(s) of metal shrapnel that tore them loose (which also would not have have had time to been reduced to small bits and dispersed). If the vane debris totally disintegrated and made it all the way to the radiators, they had to have time to do so; the pump failed first.

i completely disagree. let's say it took ten seconds from the start of the problem until the motor quit turning. at full tilt, byron was likely averaging 6,000 RPM's.

the water pump pulley is a little smaller than the crank pulley. let's say it's 15% smaller. this means the water pump would have turned 1.18 revolutions for each crank revolution.

at ten seconds, we're looking at over SEVEN HUNDRED rotations of the water pump during the failure. this is enough time to circulate the entire contents of the cooling system MANY times over. the missing debris is in the radiators.

So Jake....Have you guys ever seen a water pump that just started shedding vanes from the impeller? If the impeller was completely gone, I would be more inclined to agree with the diagnosis that the water pump impeller broke apart. Normally when we are talking about water pump failure, we are talking about bearing failure. The bearing in this water pump is perfect. The fact that just the vanes are chewed off is what led me to conclude that the engine bits from the exploding case destroyed the vanes, and not vice versa. Truth is, there is no way to be sure what really happened. It's all water under the car now!!! :D

My two concerns now are how to adequately evacuate the cooling system of debris and will it be best to go with a OEM water pump vs. after market?

Theoretically interesting, but practical experiences say otherwise. Byron is of the impression shrapnel from his grenadeing M96, complete with holes in the block, tore up the pump; but if that were the case, there is no way the engine continued to run for ten seconds after dispatching a rod through the block, or even two seconds for that matter. These engines stop pretty quickly when things are lashing around the inside. So if the shrapnel from the failure got into the pump, the engine should have already been slowing considerably. Looking at his photos of the impeller, there are no vanes at all. Small metal bits would take a lot of time to do this, so I would expect to find some fairly large metallic chunks that would be required to do that amount of damage in a very limited time in or near the pump; but none are visible in the photos, and he has not mentioned finding them. The photos also do not show the gouging in the housing, or on the impeller disc itself, which begs a question: What size and shape object(s) could have gotten into the pump and proceeded to very quickly and cleanly cut off all the vanes, and then vanish entirely (along with the vanes) without leaving any other marks? That is why I questioned the supposition in the first place, the photos do not appear to support it.

When daily drivers/street cars have the vanes break off, and then drive to my shop, and we located most if not all of the bits in or near the pump housing and thermostat housing areas, sometimes after as much as an hour’s running time…..

Quote:

Originally Posted by JFP in PA Theoretically interesting, but practical experiences say otherwise. Byron is of the impression shrapnel from his grenadeing M96, complete with holes in the block, tore up the pump; but if that were the case, there is no way the engine continued to run for ten seconds after dispatching a rod through the block, or even two seconds for that matter.

mine ran for about fifteen seconds before it stalled out. it still turned over a couple more times with the starter before it locked. byron - how long did your motor continue to turn over after you started seeing smoke? i think i remember you stating that the entire process (from the INSTANT you noticed a potential problem) took several minutes. am i correct?